In a statement Friday, the West Virginia lawmaker said he had "some real differences" with both leaders, finding fault with Obama's energy and economic policies while questioning whether Romney could understand the challenges facing ordinary people.

"I strongly believe that every American should always be rooting for our president to do well, no matter which political party that he or she might belong to," Manchin said. "With that being said, many West Virginians believe the last 3 1/2 years haven't been good for us, but we're hopeful that they can get better."

Manchin, one of the more moderate Senate Democrats, has broken with his party on several issues as he seeks re-election this year. His state has backed the Republican candidate in the last three presidential elections, and Obama did not fare well in 2008. Obama lost to GOP nominee Sen. John McCain, 56-43 percent, and was overwhelmed by Hillary Rodham Clinton in the Democratic primary, losing 67-26 percent.

Manchin, the former governor who won the Senate seat in 2010, remains popular in West Virginia and is not considered vulnerable in his rematch against Republican John Raese.

In an interview with National Journal published Friday, Manchin said he will "look at the options" in casting his presidential vote. Elaborating in Friday's statement, he criticized Romney, saying "there are many West Virginians who believe that he's out of touch, especially because of his plan to end Medicare as we know it and privatize Social Security."

He added that like many West Virginians, he has concerns "about the Obama administration when it comes to energy – coal in particular – and the need to get our financial house in order."

The administration has angered some in West Virginia with its increased scrutiny of the destructive practice of mountaintop coal mining, which is concentrated in Appalachia. It announced in 2009 that it would eliminate expedited reviews of the practice, take a closer look at 150 to 200 water pollution permits granted by the Army Corps of Engineers and reverse a Bush-era rule that let the rubble be dumped near streams.

In January 2011, the EPA took the rare step of vetoing a Corps permit – but recently a judge overturned that decision.

In addition, electric power producers have blamed air pollution regulations adopted by the Environmental Protection Agency for helping to shut down older coal-fired power plants, which were already struggling to compete because of cheap natural gas.

Manchin's possible break with the party and the president would not be a political first. In 2008, Sen. Joe Lieberman, I-Conn., backed McCain although Lieberman had been the Democratic vice presidential nominee in 2000.